Carcinogenic activity of anthanthrene on mouse skin

Dibenzo [cd, jk] pyrene (anthanthrene), considered to be noncarcinogenic, was examined for carcinogenicity in a comparative study with other polycyclic hydrocarbons. Anthanthrene induced benign and malignant epidermal neoplasms in female Swiss mice after repeated skin application. The incidence of these tumors (47%) was lower and the latency longer than those found after benzo[a]pyrene or dibenzo[a,h]pyrene treatment. Since the proportion of malignant neoplasms was similar (60%) in these three groups, the results indicate that anthanthrene is a relatively strong carcinogen. A rationale accounting for previous negative results in percutaneous experiments with this compound is suggested.